Fiend, Stage 2 (Brand of the Tyrant’s Hellfire)

As a bonus action on your turn, you can brand a creature within 60 feet of you with a fiery mark that exudes hellfire. The target must make a Charisma saving throw, and on a failed save they are branded. Whenever you hit a creature branded in this way with an attack, you deal an additional 1d6 fire damage. A creature remains branded for 1 minute. The brand disappears if the creature is knocked unconscious, enters hallowed ground, or is targeted by the remove curse spell. You may use this feature a number of times equal to your Charisma modifier (minimum of 1). You regain all uses of this feature when you finish a long rest.

Flaw

Aversion to Radiant.

If you take radiant damage, you have disadvantage on attack rolls and ability checks until the end of your next turn.